From bcc48f1a7a0d40ae2e5a26aff72c2b674fd8b596 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 8 Aug 2013 21:48:22 +0800 Subject: USB: introduce usb_device_no_sg_constraint() helper Some host controllers(such as xHCI) can support building packet from discontinuous buffers, so introduce one flag and helper for this kind of host controllers, then the feature can help some applications(such as usbnet) by supporting arbitrary length of sg buffers. Acked-by: Alan Stern Signed-off-by: Ming Lei Reviewed-by: Eric Dumazet Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/urb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/usb/core/urb.c') diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index 4e7a311ff6d7..c12bc790a6a7 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -416,7 +416,8 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) urb->iso_frame_desc[n].status = -EXDEV; urb->iso_frame_desc[n].actual_length = 0; } - } else if (dev->speed != USB_SPEED_WIRELESS && urb->num_sgs) { + } else if (urb->num_sgs && !urb->dev->bus->no_sg_constraint && + dev->speed != USB_SPEED_WIRELESS) { struct scatterlist *sg; int i; -- cgit v1.2.3